I think it is a relationships orientation for some and it is a lifestyle choice for others. While poly is marginalized, I don’t think it falls under the LGBTQIA+ umbrella. I hope my opinion helps.

There are a lot of overlapping identities. I think it is more accepted now. But that overlaps many communities that used to being marginalized. Ex queer, kink, pagan, and gamer.

These are hard questions. I hope you navigate them well and you see a happier future.

The simplified question is, Is your poly self more important than your relationship with your husband? Boath of you can choose to stay or go. What might be a good first step is therapy. It seems there are unallined needs between you two. Starting with his need for security and your need for variety.